Refractive index sensor based on high quality factor all-dielectric super surface and application

Abstract

The invention discloses a refractive index sensor based on a high quality factor all-dielectric super surface. The refractive index sensor comprises a transparent substrate and a super surface structure distributed in a periodic array on the surface of the transparent substrate. The super surface structure adopts an all-dielectric material, and has sub-wavelength thickness. The refractive index sensor provided by the invention is free of a metal structure, prevents ohmic loss and biological toxicity, and does not affect the activity of an object to be tested. Moreover, with the super surface structure, the sensor has the advantages of short action area and high-speed response. Furthermore, the sensor provided by the invention is based on a dielectric material, such as a semiconductor material, which facilitates CMOS integration in the future. Moreover, the design theory can be extended to other bands, such as the terahertz band. The dielectric super surface structure with high refractive index and low loss is used for refractive index or biomolecular fingerprinting in different working bands.

Description

technical field [0001] The invention belongs to the field of optical sensing, in particular to a refractive index sensor based on a high quality factor all-dielectric metasurface and its application. Background technique [0002] The use of optical resonance-based micro-nano structures to realize simple and high-sensitivity refractive index sensing has very important application value. Especially in the detection of biomolecules, this method avoids the complicated operation of using fluorescent dyes to label the biomolecules to be tested, and directly measures the small changes in the refractive index of the solution caused by the introduction of the molecules to be tested. A smaller detection limit of the refractive index means that a lower concentration of molecules can be detected with high sensitivity. [0003] Typical optical resonant devices used for refractive index sensing include waveguide or optical fiber structures based on microfluidic technology. Although such ...

AI Technical Summary

Problems solved by technology

The use of metal structures has several limitations: one is that ohmic losses in the metal structure make it difficult to obtain a high quality factor optical response (wider resonance peak bandwidth), which affects the detection limit / sensitivity; the other is that metal The structure is not conducive to integration with the existing CMOS process, and the metal has certain biological toxicity, which is not conducive to the application of biomolecular detection

However, the currently used two-dimensional grating structures of high refractive index media (for example, silicon disk structures) are all based on a single resonance mode, with a low degree of control freedom; and due to material loss, none of them can achieve resonance with a high quality factor below a wavelength of 1 μm. characteristics, which greatly limits its effective operating bandwidth and the further reduction of device size

[0005] To sum up, there is currently no convenient and safe solution to realize a highly sensitive refractive index sensor based on an all-dielectric metasurface structure in the wavelength band below 1 μm.

Images